A CMV-specific cell-mediated immune defect has been found in 9 young children with congenital or neonatal CMV infections. To investigate the possiblity that this defect could play a role in the pathogenesis of cytomegalic inclusion disease, we are performing an intensive epidemiologic, virologic and immunologic investigation of the role of CMV-specific cell-mediated immunity in mothers and their infants. Infants from newborn nurseries are being screened to detect active CMV infections. Those infected will have CMV-specific immune studies performed. Normal pregnant women are being studied to establish the effect of pregnancy on generalized and CMV-specific cell-mediated immunity. Infants with clinical manifestations of CMV will be followed for at least 3 years. At the present some of these infants are being enrolled on an open protocol to receive transfer factor prepared from adults shown to have cell-mediated immunity to CMV. In 2 such infants administration of transfer factor has been temporally related to cessation of viruria and acquisition of lymphocyte proliferative responses to CMV. To establish the normal kinetics of CMV humoral and cell-mediated immunity in normals, volunteers given live, attenuated CMV vaccine and adults with CMV mono are being followed.